Mick McCarthy was joking when he explained recently that the reason this season's Championship has been so tight is that "we're all as bad as each other". But the Ipswich Town manager's remark was laced with truth: ineptitude is a great leveller.

A major factor in the unprecedented closeness of the league has been that clubs who should have had an advantage have contrived to fritter it away, the witlessness of Blackburn Rovers, Wolverhampton Wanderers, Nottingham Forest and Leeds United helping to create what promises to be a tense and thrilling climax to the season on Saturday.

Long league campaigns are supposed to sort the strong from the weak but the difference has never been less clear-cut than this season, when only two positions have been determined before the final day. Cardiff City are champions and Bristol City are relegated – everything else is up for grabs, with 10 of the last 12 matches being ultimatums concerning promotion or relegation.

Hull City and Watford are still vying for the second automatic promotion spot, while Crystal Palace, Bolton Wanderers, Forest and Leicester City are contesting the last two play-off berths and seven clubs are still at risk of filling the two remaining relegation positions. The teams are squashed so tightly together that the points total required to get into the play-offs could be lower than 70 for the first time and the last relegation spot will be occupied by a team with a record high tally: no one has ever been demoted from the Championship with more than 52 points but Barnsley, who are third bottom, already have 54 and Wolves could also reach that frontier and fall.

Last season the gap between the final relegation spot and final play-off spot was 35 points – or 27 if we overlook Portsmouth's deduction for their financial problems – it now stands at 13. Such extraordinary bunching means that clubs who narrowly avoid dropping into League One can also reflect on how close they came to reaching the play-offs.

"We're on 56 points and still talking about relegation with a game left which shows you how tough the league is," says Kenny Jackett, who needs his Millwall side to win at Derby County to be sure of survival. "Should we finish the job on Saturday we'll all be looking at how far we are off the play-offs."

A common complaint among many Championship fans is that teams who have just slipped out of the Premier League benefit from an unfair head start in the race for promotion thanks to the parachute payments.

It has not transpired recently, when the payments – £48m over four years – have barely softened the landing at the lower level. In the past six seasons only four of the 18 teams who have been relegated have gone back up while receiving parachute payments.

Blackburn have made a determined effort to do so this season but botched it spectacularly. They were by far the Championship's biggest spenders in the transfer market, splashing out most of their £16m parachute income on Jordan Rhodes (£8m), Leon Best (£3m) and Dickson Etuhu (£1.6m), only to sabotage themselves with the misguided hiring and firing of managers.

Wolves have also been wasteful, retaining most of the squad who slid out of the Premier League but accelerating their downward momentum by appointing a series of inexperienced managers with totally different styles. If these clubs have cogent plans, they are not letting on.

Of the other five clubs still receiving parachute payments in the Championship, the uncertainty over Birmingham City's future means they have barely bought anyone despite selling virtually all of their former Premier League players over the past two years, while Burnley, Blackpool, Hull and Bolton have made prudence a priority and only the latter two can still get promoted.

Financial conservatism has been commendably widespread, which is perhaps surprising given that the reward for making it to the Premier League will be more lavish next season than it has ever been thanks to the new television deal. Outside of Blackburn and Cardiff, million-pound transfers have been rare.

In the absence of big permanent signings, most clubs have sought to improve their teams with loans, the most glaring example being Watford, who have borrowed almost an entire squad, mostly from Italy. That approach will be deemed a success if they better Hull's result and achieve promotion but what it means for the medium-term stability of the club remains to be seen. Ipswich have made fruitful use of loans too, with McCarthy's temporary recruits enabling him to lift the club from the bottom of the table to 11th place since taking charge in November.

That, like Hull's pre-season replacement of Nick Barmby with Steve Bruce or Bolton's capture of Dougie Freedman after dismissing Owen Coyle, is a good example of a managerial switch that paid off.

Many others have not in a division in which only nine of 24 managers have been in situ for a year or more, including Charlton's Chris Powell and Brighton's Gus Poyet, who are perhaps the highest-achieving managers of the season. Forest certainly did not benefit from replacing Sean O'Driscoll with Alex McLeish in December, although their third manager of the season, Billy Davies, could still guide them to the play-offs.

Ian Holloway left Blackpool in search of greener pastures but tinkered with Crystal Palace to such an extent that the service to the division's top scorer, Glenn Murray, dried up and the previously high-flying Eagles go into Saturday's decisive match at home to Peterborough without a win in nine matches, a collapse a lot like Leicester's, who have stuck with Nigel Pearson in the hope that he can relocate his young team's mojo.

He, like so many others, is now loitering around the last chance saloon.